Rail insulator



July 20, 1943. LE ROY M. KUBAUGH K 2,324,993

RAIL INSULATOR Filed May 29, 1941 5 Sheets-Sheet l l H 5gg-Illu li n,

ATTO RN EYS July 20, 1943- LE RoY M. KUBAUGH 2,324,993

RAIL INSULATOR Filed May 29, 1941 3 Sheets-Sheet 2 ATTORNEYS Patented July 20, 1943 .unirse s'rA'res Param orifice The Firestone Tine & Rubber Company, Akron, Ohio, 'a tonnel-ation of Ohio f Application Mayl 29, 1941, 'sensi No. :39eme 'r claims `(c1. `1in- 30) This inventionrelates to rail insulators, `and more especially it relates toinsulato-rs for third rails .such .as are used by .seme railways for supplying .electric energy tc `the motors Aof .electrically .driven rail vehicles.. I Since third railscarry relatively vhigh voltage, `they constitute a definite ,maar-d to maintenance men whose .duties require .them to Work on the .railway .right .O way, and also to others who may recklessly, carelessly, cr .accidentally come upon said right of Way. vAccordingly it has been comrnon practice to .apply a protective lacing .of dielectric material to portions of third rails in those regions 0i the right of way where the hazard is greatest, .and at places where elements of the switching or signalling system are. positioned close to the rail. Such rail insulation as previously provided has been expensive to manufacture and diiii'cult to apply, and it is to thel relief of these conditions that this Vinvention primanly is directed. v Y l z '111e chief objects of the invention are to provide improved rail insulation of the character mentioned; to provide rail insulation that readily I and easily may be applied to third rails; to provide rail insulation that will not support comm bustion; to` obviate the collection `of metallic dust on the margins of the insulator; and to provide .a .rail insulator that will hug the rail closely with- L f out requiringthe use of cement or other bonding agencies. Other objects will be manifest as the description proceeds.

Of the accompanying drawings:

Fig. I is a sectional perspective view of a third rail, and an insulator constituting one embodiment of the invention mounted thereon;

Fig. 4II is a side elevation on alarger scale, of the insulated third rail shown in Figure I;

Figure III is asection on the line IIL-III of Fig. II;

Fig. IV is a sectionon the line IV-IV of Fig.

Fig. Vwis a section on the line V-V of Fig. II;

Fig. VI is a section on the line VI-VI of Fig. I; Y

Fig. VII is a section on the line VII- VII of Fig.

Fig` VIII is plan view of another embodiment of the invention, and a third rail on which the same is mounted; k 'y Fig. IX is a section on the line IX-IX of Fig. VIII;

Fig. X is a section on .the line XX of Fig. VIII; and Y v FIgLXI is a section on the line XI-XI of Fig.

Referring irst to Fig. Ioi. dra-Wings, there .is shown third and mounted thereon is an improvedinsulating structure designated as a Whole by the lnumeral Vi l.. The rail .Ifis the .same general construction as an ordinary VTY-rail for traction purposes, and comprises the usual head, web, and flange or base, the web, however, beine lows-rand thicker than in rail. The

vrail I with insulator Ii thereon is mounted upon ,spaced apart supports, such as the support I`2,

I'that are Acomposed of porcelain or other suitable that are carried by the respective Vehicles and which slide upon the top or of the rail. As a further protection to the rail Iii a wooden 'guard I3 may be positioned above the saine and .in spaced relationthereto, guard being supported by brackets, such as the bracket Ill. `Usually an'apron I5 of dielectric material is sen cured to one marginal the guard IS and con- -stitutes a lateral shield for side of the third rail.

In the embodiment oi this invention shown in Figs. I to VII ci' the drawings, the rail insulator @III is composed of a succession of insulator units that rare mechanically interlccifted to each other vto provide a continuous insulating structure. The insulator units are of three different types, the majoritywof the units being of standard type. designated I8 in thedrawings. Of fewer number are the joint type I9 adapted to cover the splice bars and bolts ythat connect adjacent ends of the rails I9, and the extension tvpe 2! adapted to connect adjacent ends of the standard type units I8. All oi said types of units are composed pri.- marily of resilient dielectric material such as rubber composition as shown, no internal reinforcing of the materia-l being required, although a fabric reinforcing may be provided ir desired. Each insulator unit has its outwardly presented surface covered with a relatively thin layer of flexible, lire-resistant material 2| that is bonded thereto, The synthetic rubber-like material known as neoprene has been found to be satisfactory material for the facing 2 I, since neoprene in the presence of flame gives cli chlorine, which will not support combustion, and which will eX- tinguish or suppress a flame by sniothering the same. Thefpresenceof the lire-resistant facing ZI is desirable for the reason that the shoe that rides the third rail may leave the Same at curves in the trackway, and cause arcs between the shoe and rail that would burn the rubber structure of tures 25 in the offset portions of the units I 8, providing a Vmechanical interlock that prevents separation of adjacent units I8.

A In the embodiment of the invention shown in the medial region thereof. The transverse con-j.

tour of the unit closely approximates the profile of the portions of the rail enclosed thereby; Added rigidity is imparted t0 the unit by buttresses or ribs 23, 23V integrally formed on the exterior of the unit and spanning the longitudinal recess'in the unit at the region thereof that engages the web ofthe rail. At each of its ends the respective lateral walls of the unit I8 are formed with oflset portions 24, 24 that are spaced rom the surface of the rail IB a distance equal to the thickness of the wall of the unit, each of said oiTset portions being centrally formed with a substantially rectangular aperture 25.

The joint type insulatorV units I9 are designed to'embrace the third rail at the splices where adjacent Vrail units are connected to each other, which connections are made by meansof splice plates 21s 21 positioned'on opposite sides of the rail units and spanning the juncture thereof, and bolts 28, 28 that extend through said splice plates and through the webs of the abutting rail units. The respective end portions of each joint unit I9 are of the same thickness and transverse contour as the intermediate regions of the standard units I8. Intermediate said end portions the unit is formed on one side with a bulge or lateral projection 29 adapted to embrace the heads of the bolts 28 and a splice plate 21, and on the other side is formed with a similar but larger bulge or projection 39 adapted to embrace the other splice plate 21 and the nuts on the en ds of the bolts 28, as is best shown in Fig. III and Fig. IV. When a joint -unit I9 isV operatively positioned with relation to two adjacent standard units I8, the end portions of the unit I9 are disposed beneath the oiTset portions on the confronting ends of the said standard units. Each of the said endrportions of the unit I9 are formed with outwardly projecting, substantially rectangular lugs'l, 3i, Which lugs are receivable in the apertures 25 in the offset portions of the standard units I8. The arrangement provides a mechanical interlock of the units I8, I9 that prevents separation of the units and assures the uninterrupted continuity of the insulatorthroughout its length. Y The extension type insulator units 29 are shown in Figs. VI and VII. Two of the units 29 are used at the juncture of two standard u nits I8, each unit 29 being shaped to t iiush against a lateral face of the rail In. The length of each unit 2li is slightly less than the combined length of the orset portion on the adjacent ends of two Y Y the units.

abutting standard'units I8, the arrangement being such that the units 23 are snugly receivable within the offset portions of the twor adjacent Y standard units, between said olTset portions and the Vlateral faces of the rail Ill. Each unit 29 is formed, midway between its upper and klower margins, with two outwardly projecting, substantially rectangular lugs 33, 33, which lugs are spaced apart from each other longitudinally of the unit, and are snugly received in respectiveraper- .same after long periods of use.

are composed of resilient rubber composition, they are laterally stiiiened by buttress ribs 31, and they have a thin facing or" neoprene on the outer or exposed surface thereof, the rubber being fabric reinforced if desired; The base portion of the unit, that is, the portion on which the flange or base of the rail I0 rests, is somewhat thicker than the base of unit I8, and is thicker than the lateral walls of the unit 35. The marginal faces of the unit 35 are beveled as at 36, 36 so as to slope downwardly from the edges thereof that abut therrail I9, the arrangement being such as to obviate the accumulation of dust, suchas metallicdust resulting from friction between contact shoes and the rail, upon the marginalfaces of the unit. The construction is suchras to reduce the re hazard since such dust will burn in the presence of an electric arc.

The major portion of each insulator unit 35 has the transverse structure shown in fulllines in Fig. 1o. nach end portion of y,the unit t5 is stiiened, and to this end the lateral Walls thereof, in the regions designated, 38, are of increased thickness, which thickness is substantially twice Y the thickness of other regions of said lateral walls. The thickening and stiffening of the ends of the units 35 obviates collapse or sagging of the In the medial region of the unit 35, the lateral walls thereof are formed with respective outwardly bulged regions 39 and eil.' In use the said bulged" portions are positioned at the juncture of two rail units I9, over the splice plates 2? and bolts 28 thereat, the bulge 39 accommodating splice plate and Vthe heads of said bolts and the bulge 40 accommodating a splice plate andthe nuts onY the ends of said bolts, asis clearly shown in Fig. IX;`

InV order that the units the rail III when mounted thereon, theunits are molded with the Vlateral walls thereof inclined toward eachother, as indicated in broken lines in Fig. X. Said walls readily are spread apart to enable theunts to be mounted on the rail In, the tension set up in the vunit by such deformation thereof thereafter urging said Walls against the lateral faces of the rail. This feature of the invention also is employed'in the manufacture of the standard type units I3.

In mounting the units 35 upon a rail, the splices at the juncture of adjacent rails .first receive the units, the bolts and splice plates at said junctures being received within the bulges 39, l0 of Thereafter other units 35 are mounted upon rthe rail in end-to-end abutment with units already mounted thereon. Of course the bulges 39, 49. of units positioned between rail splices serve no useful purpose, but the presence of .said bulgesin all the units'obviates the necessity for joint units, such as the joint units I 9 of the previouslydescribed embodiment of the invention. Also the stiifening of the end portionsY of the units 35 obviates the necessity for extension units, such as the units 29 previously described.VY

The invention reduces the cost ofv insulating third rails,` it reduces the lire hazard incidental 35 will rrnly embracev to the use of insulators, and it achieves the other advantages set out in the foregoing statement of objects.

Other modifications may be resorted to without departing from the spirit of the invention, or the scope thereof as dened by the appended claims.

What is claimed is:

1. A rail insulator for third rails and the like, said insulator comprising a structure of dielectric material adapted to embrace a portion of a rail including the lateral faces thereof and leaving a continuous surface of the rail exposed for contact with a current collector sliding therealong, and a facing on the outer surface of said structure, said facing consisting of a material that is adapted to suppress combustion.

2. A rail insulator of the character described comprising a structurey composed primarily of resilient rubber composition adapted to embrace a rail including the lateral faces thereof and leaving a continuous surface of the rail exposed for Contact with a current collector moving therealong, and a flexible facing on the outer surface of said structure, said facing consisting of a material that is adapted to generate fumes that will suppress combustion.

3. A rail insulator of the character described comprising a flexible structure adapted to embrace a rail including the lateral faces thereof and to leave a surface of the rail exposed for contact by a current collector sliding therecver,

the Walls of said structure being laminated, one ply thereof being natural rubber composition and another ply being a synthetic rubber-like material capable of'generating flame-sino'thering fumes in the presence of combustion.

4. A combination as dened in claim 3 in which the synthetic rubber-li1e ply is disposed on the outwardly presented face of the structure.

5. A combination as defined in claim 3 in which the synthetic rubber-1ike ply is relatively thin as comparedy to the remainder of the laminated structure.

6. A rail insulator' of the character described comprising a plurality of fiexible units of dielectric material mounted end to end in a series upon a rail longitudinally thereof, and joint units of shorter length spanning the juncture of the cenfronting ends of the first-mentioned units and mechanically interlocked with the latter.

7. A rail insulator of the character described comprising an upwardly opening channel shape structure composed of resilient dielectric material adapted to t about the base, the web, and a portion of the head of a rail, said structure being of substantially uniform wall-thickness throughout and conforming to the contour of the rail, and buttress-like ribs formed at spaced points on the lateral walls of the structure to reinforce the saine.

LE ROY M. KUBAUGH 

